STUDY OF Pt CATALYST PREPARED BY METAL CARBONYL COMPLEX
Du, Hong-zhang; Fang, Lian-qing and Wu, Rong-an(Dalian Institute of Chemical Physics, Academia Sinica, Dalian 116023)
The Pt cluster catalyst was prepared by the deposition of [Pt3(CO)6]5CN(C2H5) 4]2 on the Al2O3 support and its reaction performance for n-heptane conversion under 500℃ and 1.2 MPa was studied. The results showed that the selectivity of the Pt cluster catalyst for the aromatization of n-heptane was 6 % higher than that of the conventional Pt catalyst prepared by the impregnation of H2PtCl6 on Al2O3, and the stability of the Pt cluster catalyst was also quite improved. During the decarbonyl-activation of the supported Pt complex catalyst, the disproportionation of CO to C and CO2 occurred, and thus the carbon species on the catalyst surface was forrred. Although the average Pt crystallite size determined by TEM was almost the same, the Pt crystallite of the Pt cluster catalyst had a higher homogeneity and stability than the conventional Pt catalyst. The existence of surface carbon species and the homogeneity of Pt crystallites are responsible to the high selectivity for aromatization and stability of Pt cluster catalyst in n -heptane reforming.